1. Field of the Invention
The present invention relates to a calendar mechanism-attached timepiece having a month indicator and a date indicator. Particularly, the invention relates to a calendar mechanism-attached timepiece having a month indicator and a date indicator constituted such that a month is indicated by a month indicator arranged on an inner side of a timepiece, a date is indicated by a date indicator arranged on an outer side of the month indicator, and it is not necessary to correct an indication of the date indicator at an end of a month other than February.
2. Description of the Related Art
Generally, a machine body including a drive portion of a timepiece is referred to as ‘movement’. A state in which the movement is attached with a dial, hands and put into a timepiece case to constitute a finished product is referred to as ‘complete’ of the timepiece. A side of both sides of a main plate constituting a base plate of a timepiece having a glass of a timepiece case, that is, a side having a dial is referred to as ‘back side’ or ‘glass side’ or ‘dial side’ of the movement. A side of both sides of the main plate having a case back of a timepiece case, that is, a side opposed to the dial is referred to as ‘top side’ or ‘case back side’ of the movement. A train wheel integrated to ‘top side’ of the movement is referred to as ‘top train wheel’. A train wheel integrated to ‘back side’ of the movement is referred to as ‘back train wheel’.
Generally, ‘12 o'clock side’ indicates a side for arranging a graduation in correspondence with 12 o'clock of the dial in an analog type timepiece. ‘12 o'clock direction’ indicates a direction directed from a rotation center of an indicator to ‘12 o'clock side’ in the analog type timepiece. Further, ‘3 o'clock side’ indicates a side of arranging a graduation in correspondence with 3 o'clock of the dial in the analog type timepiece. ‘3 o'clock direction’ indicates a direction directed from the rotation center of the indicator to ‘3 o'clock side’ in the analog type timepiece. Further, ‘6 o'clock side’ indicates a side of arranging a graduation in correspondence with 6 o'clock of the dial in the analog type timepiece. ‘6 o'clock direction’ indicates a direction directed from the rotational center of the indicator to ‘6 o'clock side’ in the analog type timepiece. Further, ‘9 o'clock side’ indicates a side of arranging a graduation in correspondence with 9 o'clock of the dial in the analog type timepiece. ‘9 o'clock direction’ indicates a direction directed from the rotational center of the indicator to ‘9 o'clock side’ in the analog type timepiece. Further, there is a case of indicating a side of arranging other graduation of the dial as in ‘2 o'clock direction’, ‘2 o'clock side’.
According to a calendar mechanism-attached timepiece of a first type of a background art, a 1-th date recess portion for detecting 1-th date of a date plate, and a 30-th date recess portion for detecting 30-th date of the date plate are formed at the same step layer on an inner diameter of the date plate in a direction of a rotating shaft of a date indicator driving wheel. A date feed finger and a month feed finger are provided at the date indicator driving wheel. 1-th date is detected by a 1-th date detecting portion of a 1-th date detecting lever, the month feed finger is controlled by a month feed restricting portion of a month feed control apparatus and a month is not fed by other than 1-th date. When 1-th date is reached, the month plate is fed by the month feed finger. In a case of a large month, the date plate is made to be fed by only 1 date by the date feed finger by restricting the date feed finger by a small month detecting lever. In a case of a small month, the small month detecting lever is made to be able to be rotated in the counterclockwise direction and two teeth of the date plate are made to be fed successively by the date feed finger. A 30-th date detecting lever detects 30-th date by being engaged with the 30-th date recess portion, and only when the small month detecting lever simultaneously detects a small month, the teeth of the date plate are made to be fed by 2 teeth by the date feed finger (refer to, for example, Japanese Patent Publication No. 2651150).
According to a calendar mechanism-attached timepiece of a second type of a background art, a tooth portion with which a date feed finger is brought into contact, a 30-th date recess portion for detecting 30-th date of a date plate, and a 1-th date recess portion for detecting 1-th date of the date plate are formed in steps at step layers different from each other on an inner diameter of the date plate in a direction of a rotating shaft of a date indicator driving wheel (refer to, for example, JP-A-2005-195370).
A calendar mechanism-attached timepiece of a third type of a background art is constituted such that a notched portion is provided at a date indicating member, and a month is indicated by the notched portion only when the date indicating member is disposed at a specific position (refer to, for example, JP-A-54-73667).
A calendar mechanism-attached timepiece of a fourth type of a background art includes a date drive wheel set, a year wheel includes 24 sheets of teeth twice as much as a number of months of one year, an intermediate wheel includes a first wheel brought in mesh with the year wheel and a second wheel arranged to be fixed coaxially with the first wheel, and the second wheel is constituted to be brought in mesh with a projection aligned on an inner side of a second stage of a date ring (refer to, for example, JP-A-2006-162611).
According to the calendar mechanism-attached timepiece of the first type of the background art, the 1-th date recess portion of the date plate, and the 30-th date recess portion of the date plate are formed at the same step layer, and the 30-th date detecting portion detects also the both recess portions of the date plate to pose a problem that an operation of the calendar mechanism becomes unstable. Further, according to the constitution, three control levers, that is, the 1-th date detecting lever, the small month detecting lever and the 30-th date detecting lever are arranged between the date plate and the month plate, and therefore, a problem that a structure of the calendar mechanism is complicated and downsizing of the timepiece is difficult is posed.
According to the calendar mechanism-attached timepiece of the second type of the background art, the 30-th date recess portion of the date plate engaged with the 30-th date detecting lever and the 1-th date recess portion of the date plate engaged with the 1-th date detecting lever are formed at different step layers in a thickness direction of the movement, and therefore, a problem that a thickness of the movement is thickened by increasing a thickness of the date plate.
According to the calendar mechanism-attached timepiece of the third type of the background art, a month is indicated by the notched portion of the date indicating member, and therefore, a problem that month indication is small and difficult to be viewed is posed. Further, according to the structure, a problem that month indication can be viewed only at a specific date is posed.
According to the calendar mechanism-attached timepiece of the fourth type of the background art, a problem that a structure of the date drive wheel set is complicated and the timepiece is difficult to be downsized is posed. Further, according to the structure, a problem that month indication is small and difficult to be viewed is posed.